Elizabeth Holmes makes her debut on the Forbes 400 as the youngest self-made woman billionaire at just 31. She dropped out her sophomore year of Stanford to found Palo Alto, Calif.-based blood testing company Theranos in 2003 with money she saved for college. With a painless prick, her labs can quickly test a drop of blood at a fraction of the price of commercial labs which need more than one vial.

Theranos has raised $400 million from venture capitalists, valuing the company at $9 billion, and Holmes' 50% stake at $4.5 billion. She has assembled a stellar board that includes elder statesmen George Shultz and Henry Kissinger. Last year, Walgreens, the largest U.S. retail pharmacy chain, with more than 8,100 stores, announced plans to roll out Theranos Wellness Centers inside its pharmacies.

"The minute you have a back-up plan, you've admitted you're not going to succeed."

Elizabeth Holmes

lon Reeve Musk is the South African born, Canadian-American entrepreneur, engineer, inventor and investor who is CEO and CTO of SpaceX, CEO and product architect of Tesla Motors, and chairman of SolarCity. He is the founder of SpaceX and a cofounder of PayPal, Inc., Tesla Motors, and Zip2. He has also envisioned a conceptual high-speed transportation system known as the Hyperloop. No matter what's said about Elon there's no question that he's in it for humanity.

When he became hyper-rich after eBay bought PayPal he didn't spend his millions to develop a social media app. Instead he bought into an electric car company, declared that he wanted to send astronauts to Mars and invested in solar power.

Musk will soon reveal two new Tesla products: a "home" battery and a much bigger "utility scale" battery. Effectively Tesla will offer customers the opportunity to buy (or lease) a Tesla battery without shelling out $100,000 for a Tesla vehicle.

If you're a cynic you might say that Musk is just trying to create a new story for Wall Street to counter some of the skepticism that's emerged over Tesla's immediate financial prospects. The stock has been trading higher ahead of the announcement after dipping at the end of last year (it's still well down from its peak of $219 hit last September).

But that's not what Musk is doing. If you look at his companies Tesla, SpaceX, and SolarCity it's clear that together they represent his penchant for sustainable energy and his vision for a cleaner more responsible future for mankind.

To prevent global warming you need to completely change the transportation matrix and replace the internal combustion engine all together. That is part of Tesla's role for a cleaner future. To power Tesla's cars you need electricity that isn't generated by fossil fuels. That's clearly the contribution of SolarCity in the grand scheme of things. Musk wants to capture the free energy of the Sun and help save the planet. No wonder they based the Iron Man character on him.

And just in case some extinction level event should decimate the planet or it becomes uninhabitable SpaceX could play an important role in preserving mankind with their quest to habitate Mars. As Musk puts it, "It make us multi-planetary." We could use Mars as a lifeboat. Musk's whole system runs on power gathered from the Sun and if you want to do that at any kind of scale you need to store the energy.

"When something is important enough, you do it even if the odds are not in your favor."